Tow crimper



M. SONNlNO TOW CRIMPER Aug 12, 1958 3 Sheets-Sheet 1 Filed Nov. 4, 1955 INVENTOR. MAR/0 SON/VINO .6 T T/IPNE X 1958 M. SONNINO 2,846,729

' TOW CRIMPER Filed Nov. 4, 1955 I '5 Sheets-Sheet 2 IN V EN TOR. MAR/0. SON/VINO BY HM; ff

ATTORNEY.

Aug, H2 1958, M. SONNINO 2,845,729

TOW CRIMPER Filed Nov. 4, 1955 3 Sheets-Sheet 3 l INVENTOR.

ATTOR/VE).

United States Patent Q TOW CRIMPER Mario Sonnino, Stamford, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine Application November 4, 1955, Serial No. 545,023

11 Claims. (Cl. 19-66) This invention relates to apparatus for crimping or crinkling a tow or bundle of textile filaments, especially parallel, continuous, synthetic filaments. Such a device is commonly called a tow crimper.

In the processes employed for producing spun yarn from staple fibers it is desirable to use crimped fibers, that is, fibers which have been crinkled or curled, in order to obtain superior yarns. In general, extruded fibers do not have this curl or crimp as initially produced; and, therefore, it is necessary that they be crimped or crinkled by artificial means as a prerequisite to spinning the best yarn therefrom. The crimping step is preferably carried out prior to cutting continuous filaments to staple lengths. With a crimper of the niprolls and smiling-box type, careful control of the crimping operation is necessary to obviate or minimize damage to the filaments from abrasion and/ or excessive pressure during crimping.

It is a primary object of the present invention to provide an improved device or apparatus for crimping a tow or strand of continuous filaments.

Another object of the invention is to provide an improved tow crimper wherein the sides of the tow are prevented from being differently crimped than that of the middle .of the tow.

Another object of the invention is to provide an improved tow crimper which will impart maximum uniformity of crimp to the tow.

Still another object of the invention is to provide a tow crimper which is adapted to be used in conjunction with other apparatus employed for continuously producing a crimped tow of filamentary material, and specifically a polyacrylonitrile filamentary material, that is, one which is comprised of a polymer (fiber-forming polymer) of acrylonitrile.

Other objects of the invention will be apparent to those skilled in the art from the following more detailed description and the accompanying drawing.

The present invention is concerned with certain improvements in a tow crimper of the nip-rolls and stutfingbox type, which type of crimper, for brevity, is sometimes designated merely as stufiing-box type. In the tow crimper of this invention, the stuffing-box includes a feed trumpet that tapers inwardly and extends to the nip of the crimping rolls. The tow is confined at the nip, thereby preventing the sides of the tow from being differently crimped than that of the middle of the tow. The feed trumpet may be included in an extension of the stufiiing box on the feed side of the crimper, in which case the extension further serves to provide rigid support for the stuffing box proper, the length of which is kept to a minimum in order to obtain maximum uni- Patented Aug. 12, 1958 formity of crimp. T-he crimped tow is discharged continuously through an upwardly movable discharge gate, to which is attached a loading rod that can be suitably weighted in order to provide the proper load for crimping the particular tow to the desired degree.

The tow crimper of the present invention is especially adapted for use as a unit of the apparatus disclosed and claimed in my copending application Serial No. 545,043, filed concurrently herewith, and in connection with practicing the method of producing a crimped tow of filamentary material that also is disclosed and claimed in said copending application. However, it can be used in other relationships in crimping a tow or strand of artificial filaments, especially polyacrylonitrile filamentary material, as well as various natural fibers or filaments. Thus, it can be employed in crimping a tow or bundle of many of the various vegetable fibers (especially cotton, hemp, jute, ramie and flax), animal fibers, e. g'., wool, and various uncrosslinked synthetic filaments, e. g., viscose and acetate rayons, nylon, filaments made from condensation products of terephthalic acid and glycol, filaments made from polyvinylidene chloride, vinyl chloride-vinyl acetate copolymers, etc. It is especially useful in crimping a tow of polyacrylonitrile filamentary material, numerous examples of which are given in, for example, Cresswell U. S. Patent No. 2,558,730, dated July 3, 1951, and in my aforementioned copending application; and especially polyacrylonitrile filamentary material that is produced by the process described in the aforementioned Cresswell patent.

The novel features of the invention are set forth in the appended claims. The invention itself, however, will be understood most readily from the following detailed description thereof when considered in connection with the accompanying drawing, and in which:

Fig. 1 is a perspective view of an apparatus embodying the invention;

Fig. 2 is a front sectional elevation of that part of the apparatus shown in Fig. 1 that is housed back of the crimping unit proper, and with the front of the housing removed;

Fig. 3 is a front elevation, partly in section, of part of the crimping unit proper that is illustrated in Fig. 1; and showing the passage of the uncrimped tow through the inlet or feed-in end of the stuffing-box assembly or unit, thence between the nip of the rolls, where the tow of filaments begins to bunch-up (folding back and forth upon itself) and becomes crimped by reason of the compression that builds up until the loading on the discharge gate is overcome by the internal pressure and the crimped tow is discharged from the exit end;

Fig. 4 is a longitudinal sectional view of part of the stuffing-box unit or assembly illustrated in Figs. 1 -3, and showing the discharge gate in a closed position; and

Fig. 5 is a perspective view of part of the stuifing-box unit shown in the other figures.

Referring to the drawing, the tow crimper shown by way of illustration in Fig. 1 comprises a crimping unit 10 which is exterior of, and adjacent to, a front wall 12 of a housing 14 having a removable top cover 15, which housing encloses other parts of the tow crimper. The crimping unit 10 includes parallel coacting, first and second feed rolls; and a stuffing-box unit or assembly 44 adapted to receive the aforesaid rolls in a middle part of said unit. These rolls are adjustably movable so that their peripheries can be brought close to each other thereby to nip the tow that is passed therebetween and also are adjustably movable so that they can be positioned in a plane perpendicular to the axis of said stufling-box unit.

In a preferred embodiment of the invention and as shown in Figs. 1 and 3, the parallel coacting first and second feed rolls comprise an upper roll or wheel 16 having a hub 18 keyed on rotatable upper shaft 20; and a-lower roll or wheel 22 having a hub 24 keyed on rotatable lower shaft 26. The upper roll 16 is provided with a rim 28 which is keyed in position by means of the key 30, while the lower roll 22 is provided with a rim 32 which is keyed in position by means of the key 34. The rims 28 and 32 advantageously are made of a material that will obviate or minimize the possibility of damage to the stuifing-box, e. g., a non-metallic substance such, for instance, as nylon, a laminate of cloth or other fabric material bonded together with a phenolic or other water-resistance thermosetting resin, etc. The main body portion of each of the rolls 16 and 22 is advantageously made from a suitable metal or alloy, e. g., stainless steel, chromium-p1ated brass, etc. i

The rotatable shafts 20 and 26 are suitably mounted in front and rear bearing assemblies (not shown) and wherein they are supported upon bearings that constitute an essential part of each of said assemblies. Both of these shafts, and the rolls 16 and 22 mounted thereon, are positively driven in synchronization by gear or other means (not shown) receiving power from a suitable power source (not shown).

Suitable openings are provided in the front wall 12 of the housing 14 for the passage therethrough of the front ends of the shafts 20 and 26, while the rear ends of said shafts pass through corresponding openings 36 and 38, respectively, in rear wall 108.

As shown in Figs. 1, 3, 4 and the crimping unit (Fig. 1) includes a stufling-box unit or assembly 44. This unit is held to the front wall 12 by means of screws 46 (Fig. 1), and is located by a keyway 48 (Fig. 5) on a machined key (not shown) fastened to wall 12. The unit 44 can be adjusted forward and backward, as may be required, by means of the screws 50 and 52 that contact the angle 54 which is welded, screwed or otherwise suitably attached to the end of the stufling-box unit as shown in Figs. 1 and 3.

It will be noted that the stulfing-box unit 44 has a member comprising a feed trumpet 56 (Fig. 4) that tapers inwardly and through which the uncrimped tow 58 (Fig. 3) is fed to the nip of the feed rolls 16 and 22. The member or part comprising the feed trumpet 56 may be integral with the stufling box proper and constitute an extension thereof so that it is a unitary structure as shown in Figs. 1 and 5. Although this type of construction has certain manufacturing and operating advantages, it is not essential that this be done since the member comprising the feed trumpet 56 could be separately built and then bolted or clamped to the other part of the unit 44; or it might merely be fastened to the front wall 12 so that it fitted closely to the stufiing box proper (that is, to l a point near the nip of the rolls) without being bolted, clamped or otherwise fastened to the said stuffing box. However, in the preferred embodiment of the invention the unit 44 is provided with a feed-in extension 60 (Figs. 1 and 5) having a centrally disposed, longitudinal extending tow-inlet port or opening 62 (Figs. 4 and 5) that tapers (for example, after entering the port a short distance as shown in Fig. 4) toward the nip of the rolls. The taper of feed trumpet 56 may be varied depending, for example, upon the particular tow being crimped, the conditions of crimping, the degree of crimp wanted, the rate of travel of the tow through the crimper and other influencing factors. For instance, the taper may be varied between about 4 and about however, in crimping a tow of polyacrylonitrile filaments as briefly described hereinafter and more fully in my copending application Serial No. 545,043, filed concurrently herewith, the taper of the tow-inlet port toward the .nip of the rolls preferably is about 8.

The middle part of section 64 of the stufling-box unit 44 is constructed as shown in Figs. 3, 4 and 5. It has a slot 66 adapted to receive the periphery and part of the outer edge of the upper roll 16. A similar slot is provided for lower roll 22. The upper walls 68 and 70 of this slot conform to the perimeter of the upper roll 16 while corresponding walls (not shown) of the lower slot conform to the perimeter of the lower roll 22. Minimum clearance between the sides of the feed rolls 16 and 22 and the sides of the slot (side 72 being shown in Figs. 4 and 5) are essential for optimum performance. This construction provides positive assurance that the tow will be confined at the nip of the rolls and that the sides of the tow will not be crirnped diflerently from that of the middle of the tow, which has been an outstanding fault of most of the prior art tow crimpers.

The stufiing-box unit 44 also includes a stuffing box or crimping chamber comprising a discharge trumpet that tapers toward the nip of the rolls (or outwardly from the nip as the tow is being crimped and discharged). This taper may vary, for instance, as described hereinbefore with reference to feed trumpet 56; that is, for example, between about 4 and about 15, and preferably about 8 when crimping a tow of polyacrylonitrile filaments. The stufiing box or chamber should be suitably surfaced to minimize friction, e. g., by being chromeplated and well-polished.

Extension 112 may be integral with the middle section 64 of the unit 44; or, as shown in Figs. 3 and 4, it may be rigidly but removably attached to section 64 by suitable means, e. g., by a plurality of screws, one of which is identified as 114 in Figs. 3 and 4. A gate 116 is pivotally mounted on the hinge 118 and is adapted to close the outlet of the discharge trumpet 110. The gate 116 is yieldably raisable, during operation of the tow crimper, under the pressure of the crimped tow to be discharged from the discharge trumpet 110. This gate is relatively light in weight (being made, for instance, of lightweight stainless steel), and is well-polished on its underside to minimize friction during operation. Suitable means are provided at the gate 116 for regulating the pressure in the discharge trumpet or chamber 110, which pressure causes the tow to fold over and become crimped. Such means may take the form of, for instance, a loading rod 120 which may be threaded as indicated in Fig. 4 and suitably weighted by weight 121 (or a plurality of such weights), which is held in position by means of nuts 122 and 124 on the threaded portion of the said loading rod.

The angle formed by the gate 116 and the longitudinal axis of the discharge trumpet 110 is important from the standpoint of optimum, uniform performance. This angle may range, for instance, from about 8 to about 20 depending upon such influencing factors as mentioned hereinbefore with respect to the taper of the feed trumpet 56. In the crimping of a tow of polyacrylonitrile filaments as briefly described hereinafter and more fully in my aforementioned copending application Serial No. 545,043, optimum results from the standpoint of uniformity of performance are obtained when this angle is about 12".

It is not essential that the extension 112 and associated parts such as the gate 116 be positioned as shown in Figs. 1, 3, 4 and 5, although optimum results are obtained when the extension is positioned as shown with respect to the discharge trumpet 110. The extension 112 and associated parts may be rotated about the axis of the discharge trumpet 110, for instance, at angles varying between about 0 and Air or spring-actuated means can be employed to regulate the opening of the gate 116 when its angle of mounting with respect to the discharge trumpet is such that a loading rod would be unsatisfactory or inoperative.

It is generally desirable that the feed rolls 16 and 22 be cooled by suitable means during operation of the tow crimper in order to prevent expansion due to heat. This may be done, for example, as shown in Fig. 1, by permitting, water to drip upon the sides of the wheels 16 and 22. As shown in this figure, water from a suitable supply source (not shown) is introduced through the inlet conduit 126, part of which is applied to the upper wheel 16 through the upper fork 128, while another portion is applied to the lower wheel 22 through the fork 130.

Referring now more particularly to Fig. 2, lower roll 22 (Figs. 1 and 3) mounted on rotatable lower shaft 26 is supported by means of lower linkage 74 to the housing 14 by means of lower pivot shaft 76. This arrangement allows the lower roll to be adjustable .as to its vertical position but it remains fixed with respect to its horizontal position. The upper roll 16 (Figs. 1 and 3) mounted on rotatable upper shaft 20 is connected to the housing 14 by means of two linkages, upper linkage 78 and pivot arm 79. Upper linkage 78 is connected to the pivot arm 79 by means of upper pivot shaft .80, while pivot arm 79 is connected to the housing 14 by means of pivotv arm shaft 82. Bymeans of. these linkages upper roll 16 can be adjusted with respectto both its horizontal and its vertical positions. Shafts 20 and 26 are provided with bearing caps 40 and 42, respectively.

In a preferred. embodiment of the invention, pivot arm shaft 82 is mounted on housing 14 by means of thrust bearings and it extends through an opening in, and slightly beyond, the front wall 12 of the housing 14. Upper pivot shaft 80 and lower pivot shaft 76 are also provided with thrust bearings and, in the preferred embodiment of the invention, they also extend through corresponding openings in, and slightly beyond, the front wall 12 of housing14. Lower pivot shaft 76 is fixedly mounted on front wall 12, while upper pivot shaft 80 is free to move'in a circular path about the axis of the pivot arm shaft 82. It is. not essential that shafts 76, 80 and 82 extend slightly beyond the front wall 12, which fact has been indicated in Fig. l by not showing the ends of said shafts extending beyond said wall.

Lower roll 22 is adjusted in its vertical position by means of lower roll vertical adjustment lever 84 pivoted about vertical adjustment levers pivot shaft 86 and lower roll vertical adjustment screw 87 mounted on side 88 of housing 14. Adjustment screw 87 and adjustment lever 84 will act upon lower linkage 74 against the pressure applied by air piston 90.

The horizontal position of upper roll 16 is adjusted by means of horizontal adjustment lever 92 mounted on horizontal adjustment lever pivot shaft 94 and acted upon by horizontal adjustment screw 96 mounted on side 98 of housing 14. Adjustment screw 96 and adjustment lever 92 act upon pivot arm 79 against the action of stop screw 100 also mounted on side 98 of housing 14.

The adjustment of upper roll 16 on a vertical plane is accomplished by means of upper roll vertical adjustment lever 102 pivoted on vertical adjustment pivot shaft 86 and acted upon by upper roll vertical adjustment screw 104. Screw 104 and adjustment lever 102 will act upon upper linkage 78 against the pressure applied by air piston 106. Front and back adjustment of rolls 16 and 22 is madeso that they will be properly positioned in slot 66. This is accomplished by positioning of linkages 74 and 78 on pivot shafts 76 and 80, respectively, their position being retained by locking pins 136 and 138.

The openings 140 and 142 in the side wall 83 and front wall 12, respectively, of the housing 14 provide convenient means for inspection of, and limited access to, the working parts within the housing 14 without removal of the top cover 15.

In adjusting the machine for operation, the lower roll 22 is first adjusted as to its vertical position by means of lever 84 and screw 87 acting against the pressure supplied by air piston 90. The stuffing box unit 44 is then adjusted to conform with lower roll 22 by means of screws 52 and 50. Upperroll 16 is then adjusted to conform with 6 stufling box unit 44 first by horizontal adjustment lever 92 and screws% and 100. Then the vertical position of upper roll 16 is adjusted by means of lever 102 and screw 104 acting against the pressure supplied by air piston 106.

During operation of the crimper, air pistons and 106 allow the wheels 16 and 22 to provide the necessary traction for the tow and are yieldable so that, in case of a knot or tangle in the tow, the wheels will automatically spread and permit the knot or tangle to pass through the crimping zone. without damage to. the machine.

The tow crimper of this invention is particularly suitable for use in the crimping of a tow of polyacrylonitrile filaments. Such a tow is more fully described in my aforementioned copending application Serial No. 545,043, together with a brief description of the operation of the crimper. As therein described, the tow of polyacrylonitrile filaments is preferably conditioned prior to entering the tow crimper by being contacted with a hot, aqueous fluid comprised mainly or composed solely of water. This aqueous fluid is at a temperature of from about 155 F. to about 205 F. It may be hot water alone or it may be an aqueous fluid comprising mainly water and a lesser amount of an effect agent, e. g., an antistatic material containing a low-viscosity mineral or other suitable oil; a lubricant; or any other additive that will alter the properties of the tow or improve its processability either during manufacture or in subsequent textile operations.

The wetted tow, when it enters the tow-inlet port 62, contains water in an amount corresponding to from about to about 700%, by weight, based on the weight of the bone-dry tow. The wetted and heated polyacrylonitrile tow is continuously crimped at a temperature of from about F. to about 205 F., and preferably at a temperature of from about F. to about 195 F. Most of the water with which the tow is saturated is pressed out of the tow during crimping and flows through port 62.

The crimped, hot tow 132 is discharged continuously from the discharge end 134 of the tow crimper. The temperature of the tow at this point ranges from about 150 F. to about 200 F. and, more particularly, from about F. to about F. It contains, for example, from about 50% to about 150% or 200% by weight of water, based on the weight of the bone-dry tow. The crimp in the tow is set by continuously passing the hot tow, while in a relaxed state (preferably while in a supported, relaxed state), to a cooling zone wherein the temperature of the tow is reduced to below 120 F., and preferably to a temperature not higher than about 100 F., e. g., 8090 F.

The tow crimper of the present invention provides substantial uniformity of crimp in the tow being processed and uniform performance. It is easy to adjust, operate and maintain. It can be operated for prolonged periods without maintenance. These and other practical advantages will be apparent to those skilled in the art from the foregoing description and the accompanying drawing.

I claim:

1. A tow crimper of the nip-rolls and stufiing-box type having a feed trumpet that tapers inwardly and through which the tow is fed to the nip of the rolls, thereby confining the tow at said nip, the taper of the said feed trumpet being between about 4 and about 15, and the. member comprising the said feed trumpet being integral with the stuffing box proper and constituting an extension thereof so that it is a unitary structure; a discharge trumpet that tapers toward the nip of the rolls, the taper of the said discharge trumpet being between about 4 and about 15; a pivotally mounted gate adapted to close the outlet end of said discharge trumpet and which is v yieldably raisable, during operation of the tow crimper, under the pressure of the crimped tow to be discharged from said discharge trumpet, the angle formed by the said yieldably raisable gate, when closed, with the horizontal axis of the said discharge trumpet being between about 8 and about 20; and means for regulating the pressure in the aforesaid discharge trumpet.

2. A tow crimper as in claim 1 wherein the means for regulating the pressure in the aforesaid discharge trumpet includes a loading rod mounted on the outside of the gate.

3. A tow crimper as in claim 1 wherein the taper of the feed trumpet is about 8.

4. A tow crimper as in claim 1 wherein the taper of the discharge trumpet is about 8.

5. A tow crimper as in claim 1 wherein the angle formed by the yieldably raisable gate, when closed, with the horizontal axis of the discharge trumpet is about 12.

6. A tow crimper as in claim 1 wherein the taper of the feed trumpet and of the discharge trumpet each is about 8, and the angle formed by the yieldably raisable gate, when closed, with the horizontal axis of said discharge trumpet is about 12.

7. A tow crimper comprising parallel coacting, first and second feed rolls; a stutfing-box unit adapted to receive said rolls in a middle portion of said unit, said rolls being adjustably movable so that their peripheries can be brought close to each other thereby to nip tow that is passed therebetween and also being adjustably movable so that they can be positioned in a plane perpendicular to the axis of said stulfing-box unit, the latter being provided with a feed-in extension having a centrally disposed, longitudinally extending, tow-inlet port that tapers toward the nip of the aforesaid rolls, said feed-in extension being integral with said stuffing-box unit, and said stuffing-box unit being further provided with a stuifing box comprising a discharge trumpet that tapers toward the nip of the rolls, a pivotally mounted gate adapted to close the outlet end of said discharge trumpet and which is yieldably raisable, during operation of the tow crimper, under the pressure of the crimped tow to be discharged from said discharge trumpet, and means for regulating the pressure in the aforesaid discharge trumpet, the taper of the said tow-inlet port and of the said discharge trumpet each being between about 4 and about 15, and the angle formed by the said yieldably raisable gate, when closed, with the horizontal axis of the said discharge trumpet being between about 8 and about 20; and said tow crimper also including means for adjusting said feed rolls and for maintaining them in operative relationship with each other and with said stuffing-box unit.

8. A tow crimper comprising parallel coacting, upper and lower feed rolls; and a stufiing-box unit adapted to receive said rolls in a middle portion of said unit, said middle portion being provided with upper and lower slots adapted to receive, respectively, the periphery and part of the outer edge of the said upper roll and of the said lower roll, the upper walls of the said upper slot conforming to the perimeter of the said upper roll and the corresponding walls of the said lower slot conforming to the perimeter of the said lower roll, said stuffing-box unit being provided with a feed-in extension having a centrally disposed, longitudinally extending, tow-inlet port which extends to the feed-in ends of the said slots and tapers toward the nip of the rolls.

9. A tow crimper comprising parallel coacting, upper and lower feed rolls each mounted, respectively, on rotatable upper and lower shafts; a stufiing-box unit adapted to receive said rolls in a middle portion of said unit, said rolls being adjustably movable so that their peripheries can be brought close to each other thereby to nip tow that is passed therebetween and also being adjustably movable so that they can be positioned in a plane perpendicular to the axis of said stuffing-box unit; and means for adjusting said feed rolls and for maintaining them in operative relationship with each other and with said stufiing-box unit, said means including (a) an upper linkage and a pivot arm which connect the said upper roll mounted on the said rotatable upper shaft to a housing that includes a front wall, the said upper linkage being connected to the said pivot arm by means of an upper pivot shaft and the said pivot arm being connected to the said housing by means of a pivot arm shaft, whereby the said upper roll can be adjusted with respect to both its horizontal and vertical positions, and (b) a lower linkage and a lower pivot shaft which connect the said lower roll mounted on the said rotatable lower shaft to the said housing, whereby the said lower roll can be adjusted with respect to its vertical position but remains fixed with respect to its horizontal position.

10. A tow crimper as in claim 9 wherein the pivot arm shaft is mounted on the housing by means of thrust bearings and extends through an opening in the front wall of the said housing; and the upper and lower pivot shafts are each also provided with thrust bearings and each extends through corresponding openings in the said front wall of the said housing, the said lower pivot shaft being fixedly mounted on the said front wall, while the said upper pivot shaft is free to move in a circular path about the axis of the said pivot arm shaft.

11. A tow crimper comprising parallel coacting, upper and lower feed rolls each mounted, respectively, on rotatable upper and lower shafts; a stufiing-box unit adapted to receive said rolls in a middle portion of said unit, said rolls being adjustably movable so that their peripheries can be brought close to each other thereby to nip tow that is passed tberebetween and also being adjustably movable so that they can be positioned in a plane perpendicular to the axis of said stufiing-box unit, the latter being provided with a feed-in extension having a centrally disposed, longitudinally extending, tow-inlet port that tapers toward the nip of the aforesaid rolls, said feed-in extension being integral with said stufling-box unit, and said stufiing-box unit being further provided with a stufiing box comprising a discharge trumpet that tapers toward the nip of the rolls, a pivotally mounted gate adapted to close the outlet end of said discharge trumpet and which is yieldably raisable, during operation of the tow crimper, under the pressure of the crimped tow to be discharged from said discharge trumpet, and means for regulating the pressure in the aforesaid discharge trumpet, the taper of the said towinlet port and of the said discharge trumpet each being between about 4 and about 15, and the angle formed by the said yieldably raisable gate, when closed, with the horizontal axis of the said discharge trumpet being between about 8 and about 20; and means for adjusting said feed rolls and for maintaining them in operative relationship with each other and with said stuflingbox, said means including (a) an upper linkage and a pivot arm which connect the said upper roll mounted on the said rotatable upper shaft to a housing that includes a front wall, the said upper linkage being connected to the said pivot arm by means of an upper pivot shaft and the said pivot arm being connected to the said housing by means of a pivot arm shaft, whereby the said upper roll can be adjusted with respect to both its horizontal and vertical positions, and (b) a lower linkage and a lower pivot shaft which connect the said lower roll mounted on the said rotatable lower shaft to the said housing, whereby the said lower roll can be adjusted with respect to its vertical position but remains fixed with respect to its horizontal position.

References Cited in the file of this patent UNlTED STATES PATENTS 2,311,174 I-Iitt Feb. 16, 1943 2,419,320 Lohrke Apr. 22, 1947 2,435,891 Lodge Feb. 10, 1948 2,500,690 Lannan Mar. 14, 1950 2,715,309 Rosenstein et al Aug. 16, 1955 2,734,228 Hay Feb. 14, 1956 2,740,992 Shattuck Apr. 10, 1956 2,793,418 Pfau May 28, 1957 

